Water Environment Association of Texas Peracetic Acid for Disinfection of Municipal Wastewater Effluent Dr. Carl Linden, University of Colorado Part 1: PAA Fundamentals Dr. Allegra da Silva, Stantec Part 2: PAA Current Regulatory Status & Issues Part 3: WERF LIFT PAA Study Update Webinar and CEU sheet can be found at: http://www.weat.org/peraceticacidwe binar.shtml Dr. Michael J. Watts, Garver Part 4: Case Study #1: Pilot Testing of PAA with UV Disinfection at Little Rock, AR Sarah Stewart, CDM-Smith Part 5: Case Study #2: The First Peracetic Acid Disinfection System in Texas – Up and Running Leonard Levine, Gulf Coast Authority Part 5: Case Study #2: The First Peracetic Acid Disinfection System in Texas – Up and Running
74
Embed
Peracetic Acid for Disinfection of Municipal Wastewater ...ftp.weat.org/Presentations/2017_Peracetic_Acid_Slides.pdfCalifornia Allowing trials and supplemental PAA for underperforming
This document is posted to help you gain knowledge. Please leave a comment to let me know what you think about it! Share it to your friends and learn new things together.
Transcript
Water Environment Association of Texas
Peracetic Acid for Disinfection of Municipal Wastewater
Effluent Dr. Carl Linden, University of Colorado Part 1: PAA Fundamentals
Dr. Allegra da Silva, Stantec Part 2: PAA Current Regulatory Status & Issues
Part 3: WERF LIFT PAA Study Update
Webinar and CEU sheet can be found at:
http://www.weat.org/peraceticacidwebinar.shtml
Dr. Michael J. Watts, Garver Part 4: Case Study #1: Pilot Testing of PAA with UV Disinfection at Little Rock, AR
Sarah Stewart, CDM-Smith Part 5: Case Study #2: The First Peracetic Acid Disinfection System in Texas – Up and Running
Leonard Levine, Gulf Coast Authority Part 5: Case Study #2: The First Peracetic Acid Disinfection System in Texas – Up and Running
Water Environment Association of Texas
Michael Watts, Garver Moderator
Webinar, slides, and CEU sheet can be found at:
http://www.weat.org/peraceticacidwebinar.shtml
Peracetic Acid for Disinfection of Municipal Wastewater
Effluent
Water Environment Association of Texas
Part 1: Peracetic Acid (PAA) Fundamentals
Dr. Carl Linden
University of Colorado
Water Environment Association of Texas
Part 1 Agenda
• PAA Chemistry and Composition
• Inactivation of Indicator Organisms
• PAA Residuals and Effluent Quality
• PAA Residuals and Aquatic Life
• PAA Compatibility
• Benefits of PAA
Water Environment Association of Texas
Major Classes of Disinfectants Applied for WW Treatment
Halogen-releasing
• Cl2
• HOCl
• OCl-
Peroxygens
• H2O2
• O3
• CH3COOOH Peracetic Acid
Ultraviolet
• LP
• LPHO
• Amalgam
• MP
Water Environment Association of Texas
WW market is still dominated by halogen-releasing chlorine
Chlorination
UV
Ozone
WRRFS 7 Facilities
Hypo or Gas 2009 WEF Survey of WRRF Disinfection Strategies (>4,000 facilities in U.S.)
Water Environment Association of Texas
With limited market share, why so much talk about peroxygens like PAA?
Peracetic Acid (PAA)
Inherently Safer
Stable Bulk Solutions
Low-Cost, Fast Retrofits
No Halogenated DBPs
Water Environment Association of Texas
PAA solutions are an equilibrium mixture of H2O2 and PAA
H2O2 + CH3COOH ↔ CH3COO-OH + H2O
Chemical Typical
Composition
Peroxyacetic Acid (PAA) >5%
Acetic Acid >7%
H2O2 >20%
PAA
Up to 22%
Water Environment Association of Texas
PAA is a colorless liquid, at low pH (<3), with a pungent odor
Most frequent application is
surface disinfection in medical and food
industries
Water Environment Association of Texas
When free of impurities (reducing agent, metals), PAA is stable for up to 1 year
0
0.2
0.4
0.6
0.8
1
1.2
0 2 4 6 8 10 12 14 16 18 20
Lbs/
gal
Months
Stored in original tote, or clean bulk tank
Typical 15% solution
<2% loss in strength
Water Environment Association of Texas
Unlike Cl2, low instantaneous PAA demand has been observed in secondary effluent
0
1
2
3
4
5
6
0 3 6 9 12
PA
A R
esid
ua
l, m
g/L
Contact Time, min.
Test No. 1 (HACH) Test No. 2 (HACH) Test No. 2 (I-2020)
Test No. 3 (HACH) Test No. 3 (I-2020)
Water Environment Association of Texas
PAA is an effective biocide for E. coli
-0.50
0.00
0.50
1.00
1.50
2.00
2.50
3.00
3.50
4.00
4.50
0 10 20 30 40 50 60 70
Log
Red
uct
ion
of
E. C
oli
(-
log
N/N
0)
PAA CT (mg-min/L)
20 to 30 min of contact time with a final 1 mg/L PAA residual
Batch reactor trials with tertiary effluent
Water Environment Association of Texas
A 2016 NYC DEP study found that PAA is less effective for enterococci inactivation compared to Fecal Coliform
0
5
10
15
20
25
30
35
40
Chlorine PAA
Ave
rage
CT
for
Co
mp
lian
ce, m
g-m
in/L
Fecal Coliform Enterococcus
Water Environment Association of Texas
Normalizing for other effects, PAA adds 0.9 to 1 ppm of BOD5 per ppm of PAA
Water Environment Association of Texas
If PAA residuals are relatively sturdy what effects do they have in receiving water body?
Effluent
Sample
15% PAA
PAA+Effluent
Lab
Water
0%, 31%, 41%,
55%, 74%, 98%
Serial Dilutions
Modified EPA Method 1000
C. dubia P. promelas
Water Environment Association of Texas
C.dubia shows significant sensitivity to residual PAA
Organism Survival Reproduction
C. dubia
No Effect Conc. 31% 0%
Lowest Observed Effect Conc. 41% 31%
Survival Growth
P. promelas
No Effect Conc. 98% 98%
Lowest Observed Effect Conc. -- --
Equates to a final PAA conc. of ~0.3 mg/L
Dilutions in tertiary effluent
Water Environment Association of Texas
Resolution on PAA toxicity required. . . however, in general . . .
Discharge to WW-dominated Streams
PAA Quenching Likely (e.g., Sodium Bisulfite)
Surface-spreading, Rapid Infiltration, or Ocean Discharge
PAA Quenching Unlikely
Water Environment Association of Texas
Part 2: PAA Current Regulatory Status & Issues
Dr. Allegra da Silva
Stantec
Water Environment Association of Texas
Interest in PAA
• Criteria for halogenated DBPs are becoming increasingly more stringent – PAA doesn’t form these – PAA low aquatic toxicity, relative to chlorine
• Safety of handling toxic gases including chlorine and sulfur dioxide – No Risk Management Plan (RMP)
• Low capital cost for chlorine retrofit – May not require quenching – Cheaper than capital cost to convert to UV
• Cost effective for difficult to treat wastewaters • Long shelf-life
Water Environment Association of Texas
Typical Path to PAA
Bench test
Pilot test Full-scale
trial Change permit
Install & start up
Photos courtesy of PeroxyChem
Water Environment Association of Texas
PAA in Texas
Bench test
Pilot test Full-scale
trial Change permit
Install & start up
Photos courtesy of PeroxyChem
Marshall Fort Worth North Texas Dallas Austin El Paso
PAA is a viable tool in our disinfection toolbox, supplementing our existing options Scientific and regulatory data sharing/ collaboration is critical to success of PAA
Water Environment Association of Texas
Part 4: Case Study #1 – From Pilot to Full Scale with PAA Supplemental Disinfection at
Little Rock, AR
Dr. Michael J. Watts
Garver
Water Environment Association of Texas
The Adams Field Treatment Facility (AFTF) is the largest municipal water reclamation facility in Central Arkansas
Avg. Day Q = 36 MGD
Water Environment Association of Texas
Peak influent flow at Adams Field WRRF is linked with elevated effluent E. coli
0
1000
2000
3000
20 40 60 80Treated Flow, MGD
Eff
lue
nt
FC
, C
FU
/10
0m
L
UV Disinfection at
Adams Field WRRF
Water Environment Association of Texas
Suppressed UVT has also affected the plant’s ability to meet effluent coliform limits
50 60 70 80
0.0
0.2
0.4
0.6
0.8
1.0
2011-2014
UVT(%)
Cum
ula
tive D
istr
ibution
10th percentile
Design UVT
55%
Water Environment Association of Texas
In 2014, LRW faced a key decision. . .
Replace existing UV?
Only 6 years old. . .
Supplement UV with chemical
disinfection?
Effluent permit
contained restrictive TRC limits
What about PAA?
Water Environment Association of Texas
A PAA pilot study was conducted in 2015 to assess the dosing requirements in secondary clarifier effluent that could assist UV in meeting effluent coliform limits
Water Environment Association of Texas
Key Outcomes of the Pilot Study
• PAA CT of 10 mg-min/L: <1000 cfu/100mL
• PAA CT of 20 mg-min/L: <100 cfu/100mL
• 1:1 PAA:DO increase in effluent DO
• Some pH suppression in low alkalinity effluent: ~0.3 pH units in pilot effluent
• ~1:1 PAA:BOD increase in pilot effluent
Water Environment Association of Texas
The encouraging FCB kill in the pilot study led to a full-scale trial (2016-2017)
UV
PAA Feed
Water Environment Association of Texas
Former Cl2 storage area was utilized for PAA storage and feed
Water Environment Association of Texas
New carrier piping was installed for injection of PAA into the clarifier effluent box at AFTF
Water Environment Association of Texas
Full-Scale trial testing with PAA began in 08/2016
Test Parameter
Min. PAA Dose 0.5 mg/L
Max. PAA Dose 1.5 mg/L
Data Collected
Secondary Eff. FCB, cfu/100mL
UV Influent FCB, cfu/100mL
Final Effluent FCB, cfu/100mL
Final Effluent PAA Residual
Effluent UVT, %
No. of UV Channels in Operation
UV Lamps in Operation
Effluent DO, mg/L
Effluent TSS, mg/L
PAA Feed Rate, gal/hr
Water Environment Association of Texas
PAA upstream of UV has assisted LRW in meeting seasonal effluent coliform limits
1
10
100
1000
10000
100000
1000000
cfu
/10
0m
L
Sec Eff FCB Pre-UV FCB Final Eff FCB October - April FCB Limit
Water Environment Association of Texas
During this trial period, without PAA, effluent FCB concentrations were ~1-log greater
Water Environment Association of Texas
This ~1-log FCB inactivation is occurring with relatively short PAA contact times
1
10
100
1000
10000
100000
1000000
0 2 4 6 8 10 12
cfu
/10
0m
L
Contact Time, min
Sec Eff FCB Pre-UV FCB
Water Environment Association of Texas
PAA/UV maintained a consistent effluent FCB even with variability in effluent UVT(%)
0
5
10
15
20
25
30
35
40
8/1
/20
16
8/6
/20
16
8/1
1/2
01
6
8/1
6/2
01
6
8/2
1/2
01
6
8/2
6/2
01
6
8/3
1/2
01
6
9/5
/20
16
9/1
0/2
01
6
9/1
5/2
01
6
9/2
0/2
01
6
9/2
5/2
01
6
9/3
0/2
01
6
10
/5/2
01
6
10
/10
/20
16
10
/15
/20
16
10
/20
/20
16
10
/25
/20
16
10
/30
/20
16
11
/4/2
01
6
11
/9/2
01
6
11
/14
/20
16
11
/19
/20
16
11
/24
/20
16
11
/29
/20
16
12
/4/2
01
6
12
/9/2
01
6
12
/14
/20
16
12
/19
/20
16
12
/24
/20
16
12
/29
/20
16
0.0
10.0
20.0
30.0
40.0
50.0
60.0
70.0
80.0
90.0
100.0
Eff
lue
nt F
CB
, cfu
/10
0m
L
UV
T(%
)
UVT(%) FCB with PAA & UV
Water Environment Association of Texas
Short-term PAA decay in good agreement with PAA decay observed during pilot scale treatment
0
0.2
0.4
0.6
0.8
1
1.2
0 5 10 15 20 25
PA
A/P
AA
0
Time, min
Pilot Scale Full Scale
Photodegradation?
Water Environment Association of Texas
PAA has provided the following benefits as a supplemental disinfectant to UV at Adams Field
PAA has assisted in maintaining consistent effluent FCB even with fluctuating UVT
~1-log additional FCB inactivation due to PAA
• Low initial PAA doses of 1 mg/L (on avg.)
• Short contact times (less than 10 min)
Water Environment Association of Texas
Sequential PAA/UV may not be feasible for WRRF with restrictive effluent BOD limits . . .
Sequential PAA/UV may not be feasible for WRRF with restrictive effluent BOD limits
• ~1:1 PAA Dose:ΔBOD(in effluent)
Water Environment Association of Texas
Acknowledgements
• Walter Collins, LRWRA
• John Thompson, LRWRA
• Jo Anna Brown, LRWRA
• Eric Wassell, LRWRA
• Aaron Stallmann, Garver
• Paul Strickland, Garver
Water Environment Association of Texas
Part 5: Case Study #2 – The First Peracetic Acid Disinfection System in Texas – Up and
Running!
Sarah A. Stewart, P.E. CDM Smith
Leonard Levine, P.E. GCA
Water Environment Association of Texas
GCA Overview
• Created by Legislature 1969
• Initially served Galveston, Harris and Chambers Counties, now all Texas
• No ad valorem taxes
58
Central Lab Pasadena, TX
Washburn Tunnel WWTP Pasadena, TX
Bayport Industrial WWTP Pasadena, TX
Blackhawk Regional WWTP Friendswood, TX
40-Acre Industrial WWTP Texas City Area
Odessa South Industrial WWTP Odessa, TX
Water Environment Association of Texas
Washburn Tunnel • Flow:
– Two trains for a combined flow: • 12 MGD ADF • 43 MGD PHF
• Water Quality Characteristics: – Temperature: Up to 105 degrees F – UVT: 16% – Nitrite up to 28 mg/L
• Permit Requirements: – Effluent Enterococcus: 168 CFU/100 ml as a 30-day
geometric mean – 500 CFU/100 mL Maximum Grab – Chlorine Limit: Non-detect
Washburn Tunnel WWTP Pasadena, TX
Water Environment Association of Texas
Disinfection Evaluation
DISINFECTION ALTERNATIVES
• Chlorination/ Dechlorination
• Chloramination/ Dechlorination
• UV
• Ozone
• PAA
• Ferrate
• Chlorine Dioxide
CRITERIA
• Capital/Operation and Maintenance (O&M) costs
• Performance with Varying Water Quality
• O&M Complexity and Safety
• Equipment Life Expectancy
• Expandability
• Site Impacts
• Electrical Needs versus Current Capacity
• Permitting Effort
60
Water Environment Association of Texas
Pilot Testing • GCA conducted several pilot tests:
– 5 gpm pipe reactor for 3 weeks
– Side-by-side 25 gpm pipe reactors for both chloramination/ dechlorination and PAA
Water Environment Association of Texas
Reasons for Selecting PAA
• Reduced contact time (as compared to chloramination) of 7.5 minutes
• Lower capital cost than chloramination/chlorination disinfection system
• Less variability in dosing than chloramination/chlorination under similar water quality
62
Water Environment Association of Texas
PAA Design Criteria
• Contact time: 7.5 minutes
• Design Doses: 3.5 mg/L average and 8 mg/L peak
• Temporary Quenching System was included
– Retained due to the chlorine effluent limit • PAA gives a false positive in the TRC test if present